The scene - Christmas Eve at SIL's. I love my SIL. I cannot actually imagine having a better SIL. She is much older than me and has two grown-up DCs, and they have four children. She has a small house and the dining room can only sit 8. She invited me, DH and our two galumphing teenagers (and trust me they are big), together with her and her husband, and their two children, one partner and her four, small grandchildren. So there were 9 fully grown people, and four very small people all under 5. The dining room could only sit 8, but there was a space for one person in a corner. There was a tiny table in the kitchen for the tots, which could sit 6.
So here is what happened. My SIL decided it would be a buffet, we would serve ourselves and then sit at the table. That's fine. It was kind of assumed that the parents of the small people would attend to the small people in the kitchen. But then one of the small people piped up that they wanted to sit at the big table. So the Mum of one of the small people took her three into the dining room, sat them down at the adult's table and then proceeded to take ages feeding them nothing but mashed potato and gravy.
That meant that the table intended for adults was in fact populated by three small people plus a Mum. That left only four spaces for 9 adults. We all had to make shift for ourselves. DS ate in the kitchen standing up (he couldn't fit in the small person's chair - he is a hulking rugby-player). DD sat in the Conservatory which was freezing cold. I sat in the living room which was warm but lonely.
So AIBU to think that SIL's DIL is massively selfish forcing several adults to camp out all over a small house eating solitarily, instead of feeding her children where she was intended to feed them?